WordRange

Defined in word-range.hpp.

This class implements a range object for the lower level functions cbegin_wislo and cbegin_wilo. The purpose of this class is to provide a more user-friendly interface with cbegin_wislo and cbegin_wilo.

Note

There is a small overhead to using a WordRange object rather than using cbegin_wislo or cbegin_wilo directly.

The order and range of the words in a WordRange instance can be set using the member functions:

• order
• alphabet_size
• min
• max
• first
• last

Example

WordRange words;
words.order(Order::shortlex)  // words in shortlex order
     .alphabet_size(2)        // on 2 letters
     .min(1)                  // of length in the range from 1
     .max(5);                 // to 5

Public Types
using	output_type = word_type const&
	The type of the output of a WordRange object.
using	size_type = typename std::vector<word_type>::size_type
	Alias for the size type.

Public Member Functions
	WordRange ()
	Default constructor.
	WordRange (WordRange &&)
	Default move constructor.
	WordRange (WordRange const &)
	Default copy constructor.
size_type	alphabet_size () const noexcept
	The current number of letters in the alphabet.
WordRange &	alphabet_size (size_type n) noexcept
	Set the number of letters in the alphabet.
bool	at_end () const noexcept
	Check if the range object is exhausted.
auto	begin () const noexcept
	Returns an input iterator pointing to the first word in the range.
size_t	count () const noexcept
	The actual size of the range.
auto	end () const noexcept
	Returns an input iterator pointing one beyond the last word in the range.
word_type const &	first () const noexcept
	The current first word in the range.
WordRange &	first (word_type const &frst)
	Set the first word in the range.
output_type	get () const noexcept
	Get the current value.
WordRange &	init ()
	Initialize an existing WordRange object.
word_type const &	last () const noexcept
	The current one past the last word in the range.
WordRange &	last (word_type const &lst)
	Set one past the last word in the range.
WordRange &	max (size_type val)
	Set one past the last word in the range by length.
WordRange &	min (size_type val)
	Set the first word in the range by length.
void	next () noexcept
	Advance to the next value.
WordRange &	operator= (WordRange &&)
	Default move assignment operator.
WordRange &	operator= (WordRange const &)
	Default copy assignment operator.
Order	order () const noexcept
	The current order of the words in the range.
WordRange &	order (Order val)
	Set the order of the words in the range.
size_t	size_hint () const noexcept
	The possible size of the range.
size_type	upper_bound () const noexcept
	The current upper bound on the length of a word in the range.
WordRange &	upper_bound (size_type n)
	Set an upper bound for the length of a word in the range.
bool	valid () const noexcept
	Returns whether or not the settings have been changed since the last time either next or get has been called.

Constructor & Destructor Documentation

WordRange() [1/3]

WordRange ( )

inline

Constructs an empty range with:

• min() equal to 0;
• max() equal to 0;
• order() equal to Order::shortlex;
• first() equal to the empty word;
• last() equal to the empty word;
• upper_bound() equal to 0;
• alphabet_size() equal to 0.

WordRange() [2/3]

WordRange

(

WordRange const &

)

Default copy constructor.

WordRange() [3/3]

WordRange

(

WordRange &&

)

Default move constructor.

Member Function Documentation

alphabet_size() [1/2]

size_type alphabet_size ( ) const

inlinenodiscardnoexcept

Returns the current number of letters in a WordRange object.

Returns

A value of type size_type.

Exceptions

This function is noexcept and is guaranteed never to throw.

alphabet_size() [2/2]

WordRange & alphabet_size ( size_type n )

inlinenoexcept

Sets the number of letters in a WordRange object to n.

Parameters

n	the number of letters.

Returns

A reference to *this.

Exceptions

This function is noexcept and is guaranteed never to throw.

at_end()

bool at_end ( ) const

inlinenodiscardnoexcept

Returns true if a WordRange object is exhausted, and false if not.

Returns

A value of type bool.

Exceptions

This function is noexcept and is guaranteed never to throw.

begin()

auto begin ( ) const

inlinenoexcept

This function returns an input iterator pointing to the first word in a WordRange object.

Returns

An input iterator.

Exceptions

This function is noexcept and is guaranteed never to throw.

Note

The return type of end might be different from the return type of begin.

See also

end.

count()

size_t count ( ) const

nodiscardnoexcept

Returns the number of words in a WordRange object. If order() is Order::shortlex, then size_hint() is used. If order() is not Order::shortlex, then a copy of the range may have to be looped over in order to find the return value of this function.

Returns

A value of type size_t.

Exceptions

This function is noexcept and is guaranteed never to throw.

end()

auto end ( ) const

inlinenoexcept

This function returns an input iterator pointing one beyond the last word in a WordRange object.

Returns

An input iterator.

Exceptions

This function is noexcept and is guaranteed never to throw.

Note

The return type of end might be different from the return type of begin.

See also

begin.

first() [1/2]

word_type const & first ( ) const

inlinenodiscardnoexcept

Returns the first word in a WordRange object.

Returns

A const reference to a word_type.

Exceptions

This function is noexcept and is guaranteed never to throw.

See also

min

first() [2/2]

WordRange & first ( word_type const & frst )

inline

Sets the first word in a WordRange object to be frst. This function performs no checks on its arguments. If frst contains letters greater than alphabet_size(), then the WordRange object will be empty. Similarly, if first() is greater than last() with respect to order(), then the object will be empty.

Parameters

frst	the first word.

Returns

A reference to *this.

See also

min

get()

output_type get ( ) const

inlinenodiscardnoexcept

Returns the current word in a WordRange object.

Returns

A value of type output_type.

Exceptions

This function is noexcept and is guaranteed never to throw.

Warning

If at_end() returns true, then the return value of this function could be anything.

init()

WordRange & init

(

)

This function puts a WordRange object back into the same state as if it had been newly default constructed.

Returns

A reference to *this.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

last() [1/2]

word_type const & last ( ) const

inlinenodiscardnoexcept

Returns one past the last word in a WordRange object.

Returns

A const reference to a word_type.

Exceptions

This function is noexcept and is guaranteed never to throw.

See also

max

last() [2/2]

WordRange & last ( word_type const & lst )

inline

Sets one past the last word in a WordRange object to be lst. This function performs no checks on its arguments. If lst contains letters greater than alphabet_size(), then the WordRange object will be empty.

Parameters

lst	one past the last word.

Returns

A reference to *this.

See also

max

max()

WordRange & max ( size_type val )

inline

Sets one past the last word in a WordRange object to be pow(0_w, val) (the word consisting of val letters equal to 0).

Parameters

val	the exponent.

Returns

A reference to *this.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

min()

WordRange & min ( size_type val )

inline

Sets the first word in a WordRange object to be pow(0_w, val) (the word consisting of val letters equal to 0).

Parameters

val	the exponent.

Returns

A reference to *this.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

next()

void next ( )

inlinenoexcept

Advances a WordRange object to the next value (if any).

Exceptions

This function is noexcept and is guaranteed never to throw.

See also

at_end

operator=() [1/2]

WordRange & operator=

(

WordRange &&

)

Default move assignment operator.

operator=() [2/2]

WordRange & operator=

(

WordRange const &

)

Default copy assignment operator.

order() [1/2]

Order order ( ) const

inlinenodiscardnoexcept

Returns the current order of the words in a WordRange object.

Returns

A value of type Order.

Exceptions

This function is noexcept and is guaranteed never to throw.

order() [2/2]

WordRange & order

(

Order

val

)

Sets the order of the words in a WordRange object to val.

Parameters

val	the order.

Returns

A reference to *this.

Exceptions

LibsemigroupsException

if val is not Order::shortlex or Order::lex.

size_hint()

size_t size_hint ( ) const

inlinenodiscardnoexcept

Returns the number of words in a WordRange object if order() is Order::shortlex. If order() is not Order::shortlex, then the return value of this function is meaningless.

Returns

A value of type size_t.

Exceptions

This function is noexcept and is guaranteed never to throw.

upper_bound() [1/2]

size_type upper_bound ( ) const

inlinenodiscardnoexcept

Returns the current upper bound on the length of a word in a WordRange object. This setting is only used if order() is Order::lex.

Returns

A value of type size_type.

Exceptions

This function is noexcept and is guaranteed never to throw.

upper_bound() [2/2]

WordRange & upper_bound ( size_type n )

inline

Sets an upper bound for the length of a word in a WordRange object. This setting is only used if order() is Order::lex.

Parameters

n	the upper bound.

Returns

A reference to *this.

Exceptions

This function guarantees not to throw a LibsemigroupsException.

valid()

bool valid ( ) const

inlinenoexcept

Other than by calling next, the value returned by get may be altered by a call to one of the following:

• order(Order)
• alphabet_size(size_type)
• min(size_type)
• max(size_type)
• first(word_type const&)
• last(word_type const&)
• upper_bound(size_type)

This function returns true if none of the above settings have been changed since the last time next or get is called, and false otherwise.

Returns

A value of type bool.

Member Data Documentation

is_finite

bool is_finite = true

staticconstexpr

Value indicating that the range is finite.

is_idempotent

bool is_idempotent = true

staticconstexpr

Value indicating that if get() is called twice on a WordRange object that is not changed between the two calls, then the return value of get() is the same both times.

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The documentation for this class was generated from the following file:

• /Users/jdm/libsemigroups/include/libsemigroups/word-range.hpp